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Title: Tuning ME7 with a wideband overview Post by: jibberjive on February 26, 2012, 11:13:05 PM So, much of the general tuning strategy that people talk about here is related to tuning the cars with only the stock narrowband, and consists of the tweak, log fuel trims, rinse and repeat. A lot of that can be made more efficient by having a wideband, to align requested AFR with actual. Also, people personally go about tuning different parts in different orders/ways. I know most of it is the same with a wideband, and it might simply speed up the process in some areas.
If you were to have a wideband (or do have one), what is your general overview/flowchart of tuning strategy for the ME7 maps, from scratch? Title: Re: Tuning ME7 with a wideband overview Post by: julex on March 09, 2012, 12:12:46 PM Wideband is not strictly necessary to successfully tune me 7.1 even at WOT. By employing couple of tricks, namely forcing ECU into closed-loop at WOT with retarded timing to avoid major knock and logging fuel trims there.
Then you review logs and observe fuel trims deviations. Once you find major ones (say +-5%), you adjust KRKTE at highest load and do it again. Eventually your trims at wot should be pretty close to zero at any RPM and you're done with calibrating the fueling. Now you just revert initial changes, put in whatever fueling you desire @ WOT and voila, you just calibrated your fueling at WOT without a wideband :) Having said all that I still did it with wideband and compared requested AFR to zeitronix logs and after few rounds I am within 0.1 - 0.2 of requested vs real AFR And by the way, I think I finally calibrated that HPX pretty well as well as adjusted lots of WOT fueling. You were right, it was a bit off at around 4k RPMs point - probably since I initially did all that with meth injection on which skews low RPMs/high boost part a lot into lean when meth is not spraying. The new KR based fueling doesn't have this problem anymore since once meth gets going, the knock is low and ECU pulls out fuel making the overall real AFR reasonable, unlike very rich before KR fueling. Title: Re: Tuning ME7 with a wideband overview Post by: nyet on March 09, 2012, 01:30:05 PM I have NEVER suggested tuning ME7 with narrowbands only. ALWAYS tune with a wideband sensor.
With trims only, you can only tune the closed loop operating region. You need a wideband to make sure your actual matches your request during open loop. There is no special procedure :P Title: Re: Tuning ME7 with a wideband overview Post by: pedrosousa on March 09, 2012, 01:49:25 PM In narrowband Ecu's can you just tune fuel with LAMFA or KFLBTS?? Or do you need to tune other things?
What happens when you set LAMFA at the 100% (modified axes) to 0.85??? Will you have .85? Title: Re: Tuning ME7 with a wideband overview Post by: julex on March 09, 2012, 01:57:52 PM Read my post again :). This is all theoretical on my part but if you can find where RLLRON is in our tunes, you can tell the ECU to run closed-loop (assuming lambda is specified a "1" so no BTS/LAMFA/ATR/KR Lambda lowering it in any map) at any load, including WOT. Provided timing is very low, you won't have any problems and can tune without wideband.
From our belover ME 7.1.1 document: LRS is closed for NOT (RLLRUN (nmot) <= rl <= RLLRON (nmot)) I am not saying that's recommended, but certainly doable if somebody really doesn't want to spend money on proper equipment. Title: Re: Tuning ME7 with a wideband overview Post by: julex on March 09, 2012, 02:01:24 PM In narrowband Ecu's can you just tune fuel with LAMFA or KFLBTS?? Or do you need to tune other things? What happens when you set LAMFA at the 100% (modified axes) to 0.85??? Will you have .85? Yes to your question. But please read a large "BTS" thread on this forum and then ask questions. I guarantee the thread will clarify things for you. Anyway, we are talking here about tuning of non-stock set up where he actual/real AFR, not imaginary one the ECU thinks it runs at, could be anything and it is important to measure and adjust ECU map so that theoretical matches real. To date the only way to do it on narrowband ECU is to use external wideband set up to compare AFRs and modify maps as needed. Title: Re: Tuning ME7 with a wideband overview Post by: pedrosousa on March 09, 2012, 03:51:00 PM I've been reading that thread and I use an AFR gauge, the car it's one 1.8T APY engine (512kb file), I can't get rich fuel, with TABGBTS @ 200 and KFLBTS @ .85 LAMFA with modified axes @ .85 @ row 80 and 100% I'll get 13.3 of AFR in the maximum... I'm suspecting I'm having fuel pump problems...
Title: Re: Tuning ME7 with a wideband overview Post by: nyet on March 09, 2012, 04:53:50 PM pedro: do you have logs of your req AFR? injector duty?
Title: Re: Tuning ME7 with a wideband overview Post by: pedrosousa on March 10, 2012, 03:04:46 AM It's an 1.8T norrowband ECU I don't think I have any block with Lambda request... I normally use blocks 03/20/115 I'll have to check block 2 for injector duty. If the pump has problems the injector duty will max out??
Title: Re: Tuning ME7 with a wideband overview Post by: jibberjive on March 10, 2012, 08:10:38 AM By employing couple of tricks, namely forcing ECU into closed-loop at WOT with retarded timing to avoid major knock and logging fuel trims there. So,if you knew where RLLRON is, you'd set it so that it's always less than rl, set the timing crazy low, and do some pulls while logging STFT's. Which variables do you log for STFT's, fr_w & fr2_w, frao_w & frao2_w, and/or frau_w & frau2_w?You say this is hypothetical, so I assume you haven't yet done this, right? For someone who is planning to tune with a wideband anyways, I wonder if that would be any more efficient than adjusting KRKTE for WOT open loop to match wideband, then TVUB afterwards. And by the way, I think I finally calibrated that HPX pretty well as well as adjusted lots of WOT fueling. You were right, it was a bit off at around 4k RPMs point - probably since I initially did all that with meth injection on which skews low RPMs/high boost part a lot into lean when meth is not spraying. The new KR based fueling doesn't have this problem anymore since once meth gets going, the knock is low and ECU pulls out fuel making the overall real AFR reasonable, unlike very rich before KR fueling. Sent you an email.There is no special procedure :P As the mantra of the forum as of late, there's many ways to skin a cat. So, special or not, explicitly (if you don't mind me asking) what is your general overview/flowchart for tuning ME7 with the aid of a wideband?BTW, sent you an email too re: ECuxPlot feedback. Title: Re: Tuning ME7 with a wideband overview Post by: nyet on March 10, 2012, 10:43:43 AM Julex: as usual, thanks a TON for your ECUxPlot feedback.
here's my (rough) tuning procedure http://nefariousmotorsports.com/forum/index.php?topic=617.msg8097#msg8097 ymmv Title: Re: Tuning ME7 with a wideband overview Post by: julex on March 10, 2012, 11:24:07 AM Quote from: jibberjive [/quote To tune close-loop you'd want to look at RL_W, FR_W, FR2_W and most importantly FRM_W and FRM2_W. To successfully tune with these variables you have to essentially load the engine with constant RL at a fixed RPM thresholds. How I do that is I basically speed up to whatever speed needed in 2nd or 3rd for high rpms or higher gear for low RPM tuning and while I progressivley press gas pedal i nsmall steps keeping it at each step for 5s, I apply brakes more and more to keep the car at constant RPMs. Once I log a certain RPM level from almost no pedal to as much gas until the AFRs drop (closed-loop cut off), I let the car drive easy for a long while since the brakes are red hot but I have a log with the data. I open the log, and looking at RL_W and FRM_W/FRMw_W, I see how much ECU is adding ore remove fuel from that point. If I see any significant deviation of over 5% or so, I know my fueling is way off at that Load/RPM so I modify KFLF table accordingly. Once you go through many RPM and load levels, the table will look quite different from what it was originally, I guaranteed that. Now you need to extrapolate missing points, but that's fairly easy since you'll see the pattern with you new points developing. That's for closed-loop, using traditional wideband approach you'd now log car at WOT (without any meth injection!) and observe dzwlamfaw / lamsbg_w . Compare values from your wideband logs to these values and if you're off, you adjust the values in KFLF. Once done you extrapolate these values back along load axis so that you meet smoothly with previously adjusted highest load in closed-loop, and you have now really nice and smooth fueling table. I spent several days doing that and once I was done, my fueling table eerily resembles very closely what RS4 KFLF is, not in absolute values ofc but the % changes between RPMs AFR values at given load. I will reply to your email later today. Title: Re: Tuning ME7 with a wideband overview Post by: silentbob on March 10, 2012, 11:33:21 AM Wideband is not strictly necessary to successfully tune me 7.1 even at WOT. By employing couple of tricks, namely forcing ECU into closed-loop at WOT with retarded timing to avoid major knock and logging fuel trims there. I hope this is a joke. Have you thought about EGTs and coded out EGT sensors when giving advices like this on a forum with a lot of inexperienced users? There is really no affordable alternative to a wideband sensor when tuning AFR. They are also much faster than binary sensors. Title: Re: Tuning ME7 with a wideband overview Post by: s5fourdoor on March 10, 2012, 02:33:50 PM statistically speaking, there might be more validity behind julex's point of view.
however, in practice, i'd advise against not having a wide-band gauge for safety monitoring / visualization of afr relative to driver's actions ('your actions') i don't have any plans on replacing turbos or my engine anytime soon. my plugs however were soiled by bad afr's very quickly. lol Title: Re: Tuning ME7 with a wideband overview Post by: jibberjive on March 16, 2012, 07:18:42 AM Thanks for the input everyone!
I will reply to your email later today. Julex, I don't think I ever saw your reply? If you sent one, would you mind shooting it over again? Thanks. |